Pathological morphology - degenerations, necrosis continued Flashcards
Parenchymal fatty degenerations are
change disorders of cytoplasm fat.
This degeneration can cause an increase of fat in the cell cytoplasm of these parenchymal organs, which contain small amounts of fat in normal conditions (liver, kidneys), or fat appears in the cytoplasm of cells of organs, where it is absent in normal conditions (cardiac muscles, skeleton muscles, nerve tissue etc.).
Fat of abnormal chemical composition may form in cells as a result of pathological synthesis.
Parenchymal fatty degeneration mostly occurs in
the liver, kidneys and myocardium.
Parenchymal fatty degenerations are caused by (3)
1) several contagious diseases (sepsis, tuberculosis etc.) and intoxications
2) deficiency of carbohydrates and proteins, as well as lipotropic substances (choline,
methionine, glyco-amino acids, vitamin B12 etc.
3) oxygen deficiency in tissues, caused by lung and cardiovascular conditions, blood
circulation disturbances, anemia.
With liver fatty degeneration,
small droplets of fat appear in the peripheral part of cytoplasm of hepatocytes.
The droplets relocate then to the centre and join. Finally the whole cell can fill with fat and resemble a big fat vacuoles.
With fatty degenerations the cell nucleus is damaged and symptoms of pyknosis, or lysis in more rare cases, develop. Therefore fatty
degenerations mean that fat will deposit in damaged cells.
Liver fatty degeneration is different from
physiological fat infiltration - in that case fat drops can be found in liver cells with histological methods.
Physiological fat infiltration occurs, when the liver cells are unable to process the excess fat transported to the liver by blood
and lymph and it deposits partly to cytoplasm and is consumed later by liver cells. In this case fat will deposit in unharmed cells (no changes in cell
nuclei).
In cardiac muscles, fatty degeneration is often focal. Fat deposits in
the sarcoplasm of muscle fibres. Macroscopically such focal deposits display as greyish-yellow stripes.
Cardiac muscle, viewed from the endocardium,
resembles tiger skin, with greyish yellow and brown stripes (“tiger heart”).
With renal fatty degeneration, fat will deposit in
the epithelial cells of renal tubes.
Kidneys will expand, be bigger in volume, greyish yellow, no clear-cut border between the cortex and medulla, with oily cross-section surfaces.
Mesenchymal fatty degenerations are
neutral metabolism disturbances.
Deposits of neutral fat may decrease or increase in fat depots and the stroma of several organs and lead to cachexia or obesity.
Cachexia (cachexia) is
loss of fat in fatty tissues simultaneously with
loss of free fat in organs to a bigger or smaller extent.
The causes may be starvation (alimentary fatty degeneration), also chronic debilitating contagious diseases, parasitic diseases, non-contagious diseases
(gastroenteritis, pneumonia, tumors etc).
Fat disappears from fatty tissues, which absorb serous liquid, become slimy and gelatinous, yellowish gray.
Glycoproteinosis
Carbohydrate degenerations are carbohydrate (polysaccharide, incl. glycogen, mucopolysaccharides and glycoproteins) metabolic disorders, resulting in changes of their amount and composition.
Carbohydrate metabolic disorders are best seen with
diabetes (diabetes mellitus).
The cause of diabetes is an organism’s deficiency or lack of the hormone insulin that regulates carbohydrate metabolism, glycogen depositing in tissues and organs, where it is not present in normal conditions.
Lack of insulin disturbs glycogen synthesis in muscle and fatty tissues. Glycogen deposits decrease dramatically in tissues, especially liver, where glycogen disappears totally, the liver infiltrates with fat and fatty
degeneration develops.
At the same time epithelial cells of renal tubes,
especially the loop of Henle, infiltrates with glycogen.
When the amount of glycogen builds up in cells and abnormal accumulation of glycogen appears in tissues (liver, kidneys, smooth and skeletal muscles and myocardium), the condition is called
glycogenosis or Glycogen storage disease
concrement formation
a hard lump produced by the concretion of mineral salts; found in hollow organs or ducts of the body.
petrification
also known as calcification
Calcium metabolism disturbance that causes dissolved calcium salts depositing in tissues.
The result of calcium salt deposits in tissues is concretion or calculus.
According to the underlying mechanism of calcification, two forms can be specified:
metastatic calcification and dystrophic calcification.
lime metastases
also known as Metastatic calcification occurs with general calcium metabolism disturbances and is of general character. With metastatic calcification the
salts deposit in various tissues which might be absolutely normal and healthy.
The main cause for that is hypercalcemia, which in turn can be caused by increased loss of salts from bone or disturbances in endocrine calcium salts metabolism. That is the reason why calcium metastases occur with brittle bones.
Dystrophic calcification is
pathologic accumulation of calcium salts in tissues, where metabolism has weakened or stopped. It is focal calcification; the amount of calcium salts in blood and tissue fluids has not increased.
Calcium salts accumulate in necrotic or degenerated tissues. This type of calcium salts accumulation can be a sign of self-defence of an organism.
Calcium salts may deposit around dead parasites in tissues (calcified parasite nodules), walls of blood vessels (arterial sclerosis), foci of tuberculous caseous necrosis, also dead fetuses in uterus or abdominal cavity.
lithopedion
calcified fetus, usually extrauterine
calculi, stones or concrements are deposits of calcareous material in cavities or ducts of organs.
According to the causes of formation, they are classified as
metabolic, inflammatory and obstruction concrements.
The concrements of the digestive tract are classified as real stones (calculi veri), and pseudostones (pseudoliythiases, calculi spurii) and bezoars
(bezoaria).
“Real stones”/calculi veri are
intestinal concretions or enteroliths that consist mainly of mineral salts, are layered and have a nidus (a small
foreign object – a speck of wire, a pebble, a coin etc.) with mineral salts built up in thin layers around them.
They are round and look like cobbles, smooth or rough, also their weight resembles real stones. The cross section shows they are radial (crystallised stones). Such stones form in the colon of horses mostly, but may occur with cattle as well.
Kidney and urinary calculus, bilestones, salivary stones are real stones as well.
nephrolithi, urolithi composition can be (7)
carbonates,
cystine,
oxalates,
phosphates,
uric acid,
urates,
xanthine.
cholelithi s. calculi biliares
Bile stones consist of protein main substance, calcium salt, bile pigments and cholesterin. Respectively, they can be classified as calcium, pigment and mixed stones.
sialolithi s. calculi salivales
Salivary gland stones mainly consist of calcium salts and are smooth and hard.
Sometimes the nidus is a tiny shred of straw or a single grain. Cattle may have them in the pancreatic duct, horses in parotid duct.
Pseudostones consist of
feed particles that have imbued with mineral
salts.
Pseudostones are round as well, but weigh less than real stones and vary in size (2–20 cm). They build up in the colon of horses, in more rare cases in bovine rumen and intestines, and can be single or multiple in
number.
Bezoars consist of
animal hairs or vegetable fiber and are puffy. They are found in rumen of ruminants.
Bezoars of animal hairs develop when the animal preens itself or another animal.
Necrosis is
death of single cells, groups of cells, parts of an organ or even single organs in a living organism. In a necrotic tissue all vital processes have stopped.
Often necrobiosis may precede necrosis.
necrobiosis is
is the physiological death of a cell.
This is a slow lethal process, vital functions of cells and tissues extinguish slowly. Necrobiotic processes
include advanced degenerative processes in cells that terminate with cell death (necrosis). It is identified both with and without necrosis.
Apoptosis, formerly called ‘necrobiosis’ or single cell necrosis, is programmed cell death.
According to the triggering factors the following etiological forms of necrosis are specified: (5)
1) traumatic necrosis
2) toxic necrosis
3) angiogenic or circulatory
necrosis
4) trophoneurotic necrosis
5) allergic necrosis.
pyknosis
or Karyopycnosis
degenerative state of cell nucleus/ is necrosis of cell nucleus
it shrinks and wrinkles, the internal structure fades and the nucleus is coloured very intensively with nucleus staining.
karyorrhexis
destructive fragmentation of the nucleus
Chromatin is distributed irregularly in the cytoplasm.
karyolysis
dissolution of the nucleus
plasmorrhexis
Cytoplasm coagulates (plasmocoagulatio) and ruptures, and the coagulated cytoplasm fragments into granules of various sizes.
plasmolysis
contraction of cell protoplasm due to loss of water by osmosis.
detritus
dry and structureless mass
necrosis sicca s. n. coagulativa
Coagulative necrosis is coagulation of proteins of cells and ground matter, denaturalisation and dehydration of the dead tissue.
Necrotic tissues are dry, thick, clay-coloured yellow or greyish yellow.
Ischemic stroke is an example of dry necrosis and is caused by deprivation of arterial
blood flow.
Zenker’s necrosis or degeneration, waxy necrosis in muscles, is also dry necrosis.
necrosis humida s. n. colliquativa
Liquefactive necrosis occurs in tissues that contain moisture, for example brain. Degeneration softens the dead brain tissue and develops into cerebral softening, encephalomalacia.
Macroscopically the liquefactive necrosis lesions resemble cyst and are of porridge-like or semi-liquid consistency.
Gangrene is a
specific form of necrosis, transformed by external environment.
Gangrene can be dry or wet. Gas gangrene is also known.
gangraena sicca
Dry gangrene is coagulative necrosis.
The necrotic tissues have dried due to vaporized humidity. Tissues and body parts affected by dry gangrene do not decompose, they will preserve their shape, but drying
makes them smaller, harder and black in colouring (the tissues mummify).
